This invention generally relates to using a heat exchanger to prevent a tank containing liquid from freezing or to maintain the temperature of the liquid in a tank at a desired temperature.
Certain industrial applications require large volumes of heated fluid, primarily water, but not excluding other fluids such as drilling mud, hydrocarbons or caustic solutions. Although this patent application is not limited to any one of these types of fluids, this application will refer to these fluids as water. Also, although many types of fluids, such as glycol and oil, may be used as a heat generator fluid, this application will refer to glycol as the heat generator fluid.
Specific environments, such as that of the energy industry, may require that an open flame not be present. The fluid heating system and process described herein was created to heat fluids in such environments.
Common practice, for example, has been to truck water to several tanks located at the site of an oil or gas well. The water is typically heated by open flamed trucks which utilize, for example, diesel, natural gas or propane fired burners. However, these burners are inefficient (e.g., utilizing excessive amounts of fuel) and hazardous (e.g., causing fires, severe burns, and fatalities).
A flameless heat exchanger system removes these hazards by circulating hot glycol (e.g., temperature less than 100 degrees Celsius) within the tank, and returning it to the heat source. There is no risk of explosion or burns due to open flames or high temperature steam.
The heat exchanger may be installed by inserting it into a flanged opening (e.g., four inches in diameter) in the tank, when the tank is empty. Although a four inch flange is a standard size in the oil and gas industry, the heat exchanger can be any size, and can be inserted in any size of opening. When the tanks are filled, a heater is moved to the tank site, connected to the heat exchanger, and heats the water, or any other fluid contained in the tanks, to a desired temperature. The heater generates hot glycol, which is pumped to the tanks, circulated through the heat exchanger, and returned to the heater.
This process may be continuous (or interrupted) and may be continued, for example, until the fluid in the tank is heated to the desired temperature. Multiple tanks can be heated, for example, by connecting them in series with hoses and quick connect couplers or with the use of a manifold and connected in parallel. The heating process is efficient and safe.